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| Materials can be prepared with a grain structure that permits deformation to very high plastic strains without exhibiting necking. Such materials are said to be superplastic. Super-plastic forming exploits this material property to generate shapes that have essentially constant section thickness and no re-entrant surfaces. The diagram illustrates modes for final shape generation. | ||||||||||
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In all cases, a mould is employed to define the final shape, and air pressure is used to provide a uniform deformation force on the material. The creep processes involved in deforming the metal to the final shape are slow consistent with the low superplastic strain rates. This process is best used for special, high cost, components such as the titanium fan blades of a high bypass gas turbine. From: "Manufacturing with Materials," Edwards and Endean (Eds.), Butterworth (1990) |
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